Embedded Water-based Surface Heating Part 1: Hybrid 3D Numerical Model

A numerical simulation tool that assesses the transient operation of embedded water based surface heating systems is developed. Embedded surface heating systems and especially floor heating systems are, by far, the most common heat supply system in newly built residential buildings in, for example, Scandinavia and central Europe. The thermal system operation is influenced by the transient interaction between embedded elements, zones, construction elements, systems, gains, and weather. Thus, an integrated modeling principle, based on the International Building Physics Toolbox in Simulink©, is applied where the embedded surface heating model is represented by a module. The integrated tool is suitable for thermal system analysis of whole buildings. In particular, the embedded surface heating model simultaneously calculates the transient heat conduction that occurs within the embedded element, based on the finite control volume method, and the fluid temperature decline based on a local quasi steady state assumption. The numerical model, which represents a section plane of the embedded construction, is verified against a commercial 2D heat transfer software in the case of a typical floor heating application.